@Bob Carlson.
I print screw threads vertically - several components I make for our
machines have printed screws:
A clamp - all in PLA - the clamp part took a lot of (re)-designing to
prevent bending [and snapping] under load.
I print this screw with the following settings - this screw is 16mm in
diameter with a pitch of about 4mm:
0.16mm layer height, 5 walls [2mm], Z seam random, infill 30% gyroid.
The second one is a pinch clamp, again vertically printed in PLA, but
its only 10mm in diameter, with a 2mm pitch, 3 walls at the same layer
height and infill.
Being so 'thin' it is prone to snapping at the thread root, so for the
length of the screw thread I embed an empty 'cylinder', creating a void
in the centre, the slicer sees this as a wall, so it gets the same
processing applied - a 1.2mm walled hollow section, being cylindrical it
has no stress raising corners and problem solved. Its invisible and
nobody is any the wiser - I think I saw Angus on Maker's Muse You Tube
channel doing something similar, so I'm not claiming originality.
BTW random Z means there is no continuous seam up the thread in one
place [but you knew that already :-)].
Printing gears is 'interesting', the change gears on a mini lathe are
mostly injection moulded so have no directional alignment in the
material, 3d printing straight gears results in much stronger gears
owing to the wall alignment - but the weakest link is always supposed to
be the woodruff key for a metal gear train in the event of a jam, not
the teeth :-).
Bevel gears are trickier, I print them on their back if they are large,
or teeth down with a spacing ring to lift them off the print surface -
we've had more issues with teeth shearing on bevel gears owing to the
orientation - 3 to 4 walls, for a 4 inch bevel with 30 teeth we use 15%
gyroid - from our experience gyroid infill works.
Examples from the past: Myford lathes had 20dp machined cast iron gears
with woodruff keys, but a 1974 Volvo 144 had a cam drive gear machined
from tufnol + woodruff key, quiet, but it did strip eventually.
HTH Roger.
@Bob Carlson.
I print screw threads vertically - several components I make for our
machines have printed screws:
A clamp - all in PLA - the clamp part took a lot of (re)-designing to
prevent bending [and snapping] under load.
I print this screw with the following settings - this screw is 16mm in
diameter with a pitch of about 4mm:
0.16mm layer height, 5 walls [2mm], Z seam random, infill 30% gyroid.
The second one is a pinch clamp, again vertically printed in PLA, but
its only 10mm in diameter, with a 2mm pitch, 3 walls at the same layer
height and infill.
Being so 'thin' it is prone to snapping at the thread root, so for the
length of the screw thread I embed an empty 'cylinder', creating a void
in the centre, the slicer sees this as a wall, so it gets the same
processing applied - a 1.2mm walled hollow section, being cylindrical it
has no stress raising corners and problem solved. Its invisible and
nobody is any the wiser - I think I saw Angus on Maker's Muse You Tube
channel doing something similar, so I'm not claiming originality.
BTW random Z means there is no continuous seam up the thread in one
place [but you knew that already :-)].
Printing gears is 'interesting', the change gears on a mini lathe are
mostly injection moulded so have no directional alignment in the
material, 3d printing straight gears results in much stronger gears
owing to the wall alignment - but the weakest link is always supposed to
be the woodruff key for a metal gear train in the event of a jam, not
the teeth :-).
Bevel gears are trickier, I print them on their back if they are large,
or teeth down with a spacing ring to lift them off the print surface -
we've had more issues with teeth shearing on bevel gears owing to the
orientation - 3 to 4 walls, for a 4 inch bevel with 30 teeth we use 15%
gyroid - from our experience gyroid infill works.
Examples from the past: Myford lathes had 20dp machined cast iron gears
with woodruff keys, but a 1974 Volvo 144 had a cam drive gear machined
from tufnol + woodruff key, quiet, but it did strip eventually.
HTH Roger.
